• 고무기술
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• 제12권1호
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• pp.1-7
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• 2011

Nanotechnology is the fast becoming key technology of the $21^{st}$ century. Due to its fascinating size-dependent properties, it has gained significant important in various sectors. Myths are being formed on the proverbal nanotechnology market, but the reality is the nanotechnology is not a market but a value chain. The chain comprises of - nanomaterials (nanoparticles) and nanointermediates (coatings, compounds, smart fabrics). Elastomer based nanocomposites reinforced with low volume fraction of nanofillers is the first generation nanotechnology products and it has attracted great interest due to their fascinating properties. The incorporation of nanofillers such as nanolayered silicates, carbon nanotubes, nanofibers, metal oxides or silica nanoparticles into elastomers improves significantly their mechanical, thermal, barrier properties, flame retardency etc., Extremely small particle size, high aspect ratio and large interface area yield an excellent improvement of the properties in a wide variety of the materials. Uniform dispersion of the nanofillers is a general prerequisite for achieving desired properties. In this paper, current developments in the area of elastomer based nanocomposites reinforced with layered silicate and carbon nanotube fillers are highlighted.

• 한국세라믹학회지
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• 제33권8호
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• pp.871-876
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• 1996

It is believed that fly ash could be suitable for preparing the sialon by carbothermal reduction method because the total amount of SiO2 and Al2O3 is above 80% and the unburned residual carbon is above 5% within the fly ash. The effects of reaction temperature (1350, 1400, 145$0^{\circ}C$) reaction time (1, 5, 10 hours) and the amount of carbon additions (C/SiO2=2, 3, 4 mole) on the $\beta$-sialon synthesis were obserbed, It was conformed that $\beta$-sialon (Z=2.15~2.18) was formed as major phase under all of the synthesis conditions and small amount of Si2ON2 SiC, AlN and Si3N4 was formed depending on the synthesis conditions. FeSix intermetal-lic compound was formed above 140$0^{\circ}C$ reaction temperature due to the large amount of iron oxides within the raw fly ash.

• 한국수소및신에너지학회논문집
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• 제18권3호
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• pp.301-308
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• 2007

Silicate mineral serpentine with magnesium and calcium was selected as a mineral carbonation mediators for carbon dioxide storage. Serpentine has various metallic elements as an oxides form of magnesium, iron, calcium, aluminium etc. Magnesium and calcium could be carbonation salt preferentially than other metal component within serpentine. Systemic thermochemical treatment for serpentine could change physicochemical properties like a surface area and pore dimensions. Due to the rapid chemical reaction rate depended on dimensional values, carbonation formation could determined by surface property change of thermochemical treated serpentine.

• 한국자동차공학회논문집
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• 제22권2호
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• pp.37-43
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• 2014

Exhaust emissions were studied as a function of gasoline olefin composition in two vehicles-MPI and GDi engine equipped vehicles. Three different gasolines were tested which varied in olefin contents-12, 16 and 20 vol%. Exhaust emissions in two vehicles were affected by changes in gasoline olefin composition. Responses to changes in olefins were similar in both vehicles : reducing olefins lowered emissions of NOx and CO. Measured exhaust emissions included total hydrocarbons (THC), oxides of nitrogen (NOx), carbon monooxide(CO), carbon dioxide($CO_2$), formaldehyde, benzene, toluene, xylene, 1,3-butadiene and acetylene.

• 동력기계공학회지
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• 제13권3호
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• pp.5-10
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• 2009

This work deals with a controlled auto-ignition (CAI) single cylinder gasoline engine, focusing on the extension of operating conditions. The fuel is injected indirectly into electrically heated inlet air flow. In order to keep a homogeneous air-fuel mixing, the fuel injector is cooled by the water of a specially designed coolant passage. The engine emission characteristics were investigated under the wide range of operating conditions such as 32 to 63 in the air-fuel ratio, 1000 to 1800 rpm in the engine speed, and 150 to $180^{\circ}C$ in the inlet air temperature. The ultra lean-burn can be achieved by the auto-ignition of gasoline fuel due to the heated inlet air in the compression ignition gasoline engine. It is confirmed that the emission concentrations of carbon monoxide, hydrocarbons and nitrogen oxide can be significantly reduced by CAI combustion compared with the combustion of a conventional spark ignition engine.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.16-19
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• 2006

Humin is the insoluble fraction of humic materials and play an important roles in the irreversible sorption of hydrophobic organic contaminants onto soil particles. However, there have been limited knowledge about the sorption and chemical properties of humin due to the difficulties in its separation from the inorganic matrix(mainly clays and oxides). In this study, do-ashed humin was isolated from a soil sample after removing free lipid and alkali-soluble humic fractions followed by dissolution of mineral matrix with 2% HF, and characterized by elemental analysis, C-13 NMR spectroscopic method. Sorption behavior of 1-naphthol with humin was also investigated from aqueous solution. C-13 NMR spectra indicate that humin molecules are mainly made up of aliphatic carbon including carbohydrate, methylene chain etc.. Sorption intensity for 1-naphthol was increased as organic carbon content of humin increased and log Koc values for the 1-naphthol sorption were determined to be ${\sim}3.12$

• 한국표면공학회지
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• 제48권3호
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• pp.110-114
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• 2015

The effect of hot-dip aluminizing on the corrosion of the low carbon steel was studied at $650-850^{\circ}C$ for 20-50 h in $N_2/0.5%\;H_2S$ gas. The aluminized steel consisted primarily of the Al topcoat and the underlying Al-Fe alloy layer. Aluminizing drastically improved the corrosion resistance by forming the ${\alpha}-Al_2O_3$ surface scale. Without aluminizing, the steel formed nonadherent, fragile, thick scales, which consisted of FeS as the major phase and iron oxides such as FeO, $Fe_3O_4$ and $Fe_2O_3$ as minor ones.

• 한국표면공학회지
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• 제34권1호
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• pp.49-55
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• 2001

The addition of organic compound containing -COOH, X$800_2$, -CHO group such as formic acid, formamide, formaldehyde or diethyleneamine to a chromium electroplating bath results in a chromium deposit in which carbon is incorporated. Such deposits have fewer defects than chromium layers produced by a conventional method. It was found that the as-deposited layers were amorphous and auger electron spectroscopy (AES) showed that carbon is distributed uniformly in the deposit. During heat treatment, Cr-C deposits began to crystallize at $400^{\circ}C$, and at $800^{\circ}C$ they were crystallized into chromium carbides and oxides. The effects of current density, amount of additives, applied current waveform on Cr-C alloy electroplating were examined.

• 에너지공학
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• 제8권2호
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• pp.279-284
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• 1999

국내 무연탄의 질소 산화물과의 반응 특성을 알아보기 위하여 열중량분석기에서 등온 반응 실험을 행하였다. 사용 무연탄은 도계무연탄이며, 순수한 탄소인 SP-1 흑연이 비교 시료로 선택되었다. 탄소-NO 및 탄소-$N_2$O 반응은 55$0^{\circ}C$~90$0^{\circ}C$범위의 등온 조건과 기체 분압 5kPa~20 kPa조건에서 온도와 기체 분압의 영향을 실험하였다. NO 반응에서는 NO 분압에 대한 차수는 0.45~0.96 범위이었고, 활성화에너지는 39 kJ/mol~112 kJ/mol 범위의 값을 나타내었다. $N_2$O 반응에서는 $N_2$O 분압에 대한 차수는 0.62~0.87 범위이고, 활성화에너지는 190 kJ/mol~215.3 kJ/mol 범위의 값을 나타내었다. 무연탄 연소반응과 비교하면 $700^{\circ}C$ 이하에서는 $O_2$>NO>$N_2$O 순으로 반응속도가 변화하였고, $700^{\circ}C$ 이상에서는 $O_2$>$N_2$O>NO 순으로 반응속도가 빠르게 나타났다.

• 한국자동차공학회논문집
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• 제19권4호
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• pp.16-23
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• 2011

Low temperature combustion is one of the advanced combustion technology in an internal combustion engine to reduce soot and nitrogen oxides simultaneously. In present experiment three kinds of injector were used to investigate the influence of injection angle and number of nozzle holes on the low temperature combustion in a heavy duty diesel engine. Low temperature diesel combustion is realized from the exhaust gas recirculation rate of 60%. Indicated mean effective pressure of low temperature combustion corresponds to the 70% level of conventional diesel engine combustion. Reduction of hydrocarbon and carbon monoxide, which are produced in low temperature combustion because of the low combustion temperature and a deficit of oxygen, was achieved by using various injector configuration. The result of experiment with $100^{\circ}$ injection angle and 8 holes showed that reductions in hydrocarbon and carbon monoxide could be achieved 58% and 27% respectively maintaining the 7% increased indicated mean effective pressure in low temperature diesel combustion compared with conventional injector.